The Korea Customs Service announced on Monday it had referred about 25 people who illegally copied Nintendo computer games and illegal cartridges to prosecutors for investigation.

The alleged violators of the copyright law, unearthed by the KCS, include 15 online shopping mall managers who sold over 90,000 pirated games of the Japanese game company and also illegally produced cartridges. The pirated goods are worth at least 100 billion won ($87.2 million), according to the KCS.

The illegal cartridges including R4, DSTT and DSTTi are devices that terminate piracy-prevention programs in Nintendo games. When a pirated game is connected to a Nintendo game console through the cartridge, the console is known to recognize the game as authentic.

A KCS official announces its confiscation of illegally copied Nintendo games on Monday. (Yonhap News)

The alleged violators are suspected of having sold a set of one cartridge and one memory card that can hold games for between 40,000 won to 100,000 won. The memory card, up to 16GB in capacity, could save up to 300 games.

They even advertised it as a “100 percent authentic” product guaranteed with “perfect after-sales service,” according to the KCS.

They saved games in the memory cards before sending them or had customers download games from online file-sharing websites, the officials said.

To hide from the authorities’ supervision, they opened shopping malls on overseas websites, frequently changed the online shopping mall’s IP address or managed the mall at PC rooms, KCS said. They also hired part-time workers to manage the online mall and used bank accounts and phones in other people’s names.

Expecting that such sales of pirated games may surge around Children’s Day, the KCS has been operating a investigation team consisting of 30 investigators since April.

“Considering that most of the game users are adolescents and children, such illegal purchases will make the kids less guilty in terms of illegal acts,” warned Min Byeong-jo, an official at the KCS.